“…So, in assuming the soundness of multiple realizability arguments of this sort, I in effect assume that proposals appealing to biconditional determination relations, including Sider's proposal, are off the table. 9 See [Audi, 2012], [Correia, 2010], [deRosset, 2010[deRosset, , 2011[deRosset, , 2013, [Fine, 2001], [Rosen, 2010], [Schaffer, 2009], and [Trogdon, 2009]. is highly plausible to think that both Thomson and Obama are successful in virtue of two facts: that Thomson is successful, and that Obama is successful. (This last case illustrates the idea that the 'in virtue of' operator that we use to express ground may take more than one sentence in its explanans place.)…”